1. Field of the Invention
This invention relates to spindle locking systems for power tools, and particularly to a replaceable spindle lock system for an abrading tool in which a lock member is normally biased out of engagement with a driven member. The lock member is removed by depressing it inwardly towards the driven member against the urging of biasing means mounted in the tool housing, until an exposed end of the lock member clears an externally-accessible retaining member. The retaining member is then moved out of engagement with the lock member, thereby allowing the lock member to be removed.
2. Description of The Prior Art
When it is desired to change a driven element of a power tool, (as in the abrading member for a grinder) it is necessary to retrain the driven element from rotation relative to the tool. A spindle lock is often used to lock the driven element against movement. Occasionally the spindle lock is damaged upon engagement with the driven element. Then under conventional systems it becomes necessary to replace several parts of the spindle lock assembly, often involving disassembly of the power tool adjacent the spindle lock. An example of such a system uses a lock pin which is depressed against the force of a spring to engage a rotatable gear. The lock pin is retained in place by a snap ring mounted into an annular groove on the lock pin within the tool housing interior; therefore the tool must be disassembled to replace the lock pin.
Another exaple of a spindle lock is one in which a spindle lock pin has an annular shoulder formed thereon which is trapped by an internal ledge formed in the tool gear case housing. Again the tool must be disassembled to remove the lock pin.
The present invention solves these problems by introducing a lock member and an external retaining member which coact to keep one another connected to the tool, until the lock member is depressed a predetermined distance into the housing.